As part of our new project with Yellow-billed Cuckoos, we have fitted the first 6 birds with radio-transmitters. To find out more or to support this project please click here. If you want to name a cuckoo and follow its subsequent migration, donate $100 or get the same amount together between friends – note, there are just two cuckoos left to be named.

The team behind Crossing the Caribbean are currently raising funds to work on the migration of Yellow-billed Cuckoos in northern Colombia. Please support this exciting project at www.experiment.com/cuckoo-migration/

Welcome to the blog for our project “Crossing the Caribbean: Identifying critical fuelling sites for Neotropical migrants in northern Colombia”. Here you will find information (see ‘English Content’ link) and updates from the field, including capture totals of migratory birds. Although updates are in Spanish, English summaries will be added regularly. This project is run by SELVA and financed by The Rufford Small Grants Foundation, Environment Canada and Cornell Lab of Ornithology.

If you wish to cite any of the information in this blog please consult the advice under contacto/contact us. Reproduction of any of the data or photos included on this site requires strict written permission from SELVA.

English: We have delayed publishing a summary of this fall’s observation totals in the Darién, largely because the birds keep passing. Nonetheless, we think that we have now seen the last big movement of Turkey Vultures (29th Nov) and that the final total will not change much more. So, talking of the final total, not only did we pass the million bird mark for the second year in a row but we also passed another landmark by counting a massive 1,269,450 individuals of the main diurnal migratory species (see Table). This fantastic count for Colombia is largely thanks to an excellent migration of Turkey Vultures over Sapzurro and Capurganá this year, which passed the 700 thousand birds for the first time. This represents nearly a quarter of the World population of this migratory subspecies of Turkey Vulture! The vultures also contributed to a record breaking total of raptors which surpassed 800,000 individuals.

Other species also had a record year and the totals for Common Nighthawk (21,992) and Dickcissel (30,268) were particularly notable. It’s not clear why these totals were almost double those in previous years but we will never forget the day when 8,000 Dickcissels were recorded before 10 am! Not all species fared so well and the counts of swallows this year were conspicuously low. Relative to the last two years, the numbers of Cliff Swallow and Barn Swallow in 2015 were about half what we expected. Aside the diurnal migrants, there are a number of observations of unusual species in Sapzurro that are worth mentioning, including 4 Cerulean Warblers, 5 Blackpoll Warblers, 1 Blue Grosbeak and 8 Bobolink.

¡Spiza americana! – Dickcissels!

That leaves us to thank our excellent team of observers, in particular Martha Rubio and Wil Peñalosa, who counted the vast majority of the raptors, and also to Angela Caguazango, Nick Bayly and Laura Cárdenas. We thank the community councils of Sapzurro and Capurganá for supporting our work in the region and Environment Canada for financial support.

English: The Turkey Vultures just keep coming, with another big day on the 11th (>40,000) and they have really been putting on a show (see photos). We are expecting a major movement this weekend (thanks to Panama Audubon for reporting a major movement in northern Panama), so if you can make it to Capurganá, San Francisco, Bocas del Atrato and or anywhere nearby for a weekend break, don’t forget to look up every now and then.

English: The 2015 fall migration season in the Darién was full of surprises and as might be expected in a year in which the El Niño phenomenon was impacting ecosystems across the globe, few species followed the pattern of previous years. So to begin this summary for the banding/ringing station, it is worth noting that the total number of captures set a new record (2,364), beating the record set last year (2,272). This increase may be explained in part by the addition of a new and very successful canopy net, which also likely explains the increase in species such as Red-eyed Vireo, Yellow Warbler and Tennessee Warbler. However, for other species that had their best year to date, such as Swainson’s Thrush and Veery, it is likely that other factors such as a productive breeding season, or reduced mortality during migration, might explain the increase in numbers. It is noteworthy that several species of concern had their best year yet (e.g. Golden-winged and Cerulean Warbler) or were captured for the first time (e.g. Olive-sided Flycatcher). Other highlights involving rare species included the first two Blackpoll Warblers to be captured in the Tacarcuna reserve, a Worm-eating Warbler, an Ovenbird and a Kentucky Warbler.

Not all species had a good year and it is notable that the flycatchers as a group showed markedly lower abundances compared to other years, as did several warblers, including Mourning Warbler and Canada Warbler. The latter two warblers and the Empidonax flycatchers, in particular, favor a migration route that circumvents the Gulf of Mexico taking birds overland through Mexico and Central America. It is tempting to speculate that the drying effect of the El Niño reduced food supplies along this route and may have affected the survival of these species. Equally, factors on the breeding grounds may have been responsible, reducing food supplies for flycatching species.

How varying conditions affect the survival of birds during migration remains largely unexplored and we still have much to learn regarding how changes at sites used on migration may be driving population declines.

Finally we would like to thank our excellent team of bird banders, including Angela Caguazango, Marta Rubio, Laura Cárdenas and Nick Bayly, as well as the Tacarcuna Reserve in Sapzurro for opening their doors to this research project, and to the community councils of Sapzurro and Acandí North (COCOMANORTE).

English: The mist-netting station is now closed for the season but Marta Rubio and Wilberto Peñalosa continue to count raptors in Sapzurro and Capurganá. We have had some great movements over the last four days, although there are now very few Swainson’s Hawks (2,266) and Broad-winged Hawks (670). Between 20,000 and 30,000 Turkey Vultures have been passing each day, except for a super movement of 85,075 on the 8th!